Fuse for projectiles



Feb. 4, 1947. J. B. sEMPLE I FUSES FOR PROJECTILES 2 Sheeis-Sheet l 4mvEi -roR MM 1? MW ,MMJW/ Filed Aug. 12, 1941 Feb. 4, 1947. J. B. SEMPLE,415,

FUSES FOR PROJEGTILES Filed Aug. 12, 1941 2 Sheets-Sheet 2 Patented Feb.4, 194? This invention relates to fuses for projectiles, and, moreparticularly, to point fuses that include in their structure a firingpin which, under the stress of impact, is driven rearwardly to penetrateand fire the primer or equivalent element. The invention consists in arefinement of structure that insures thesuccessful rearward drive of thefiring pin through a widened range in the angle of impact.

Ordinarily, in fuses of the type under consideration, the firing-pinextends within and normally protrudes forwardly from an axial bore thatopens at the tip of the fuse body. This protruding firing pin makesimmediate impact upon the surface of the target, and in consequence ofsuch impact is driven rearward in its bore to perform its intendedpurpose. If, however, the impact be at a low angle to the surface uponwhich impact is made, so that the component of the force that tends topress the firing pin against the wall of the bore exceeds the componentthat tends to drive the pin rearward, the latter force is ineffective;the firing pin will bind in the bore, and will not function. Thecritical angle varies somewhat, depending upon proportions. mate rials,and condition of surfaces, but will ordinarily be approximately 25. Inparticular cases-in anti-aircraft service, for example-it becomes amatter of great importance and value to accom plish what by thisinvention I have accomplished: the functioning of the shell, even thoughthe angle of impact be substantially less than the critical angle justmentioned.

In the accompanying drawings Fig. I is a view in axial section of aparticular fuse of the type indicated, in which the feature of thisinvention is incorporated. Fig. 51 is a similar view (though partly inelevation) that illustrates diagrammatically the mode of operation;Figs. III, IV, V, and VI are similar views, illustrating variations indetails of structure; Figs. VII and VIII are views corresponding toFigs. I and II in which a firing pin of specifically different structureresponds in different manner to the stress of impact; and IX, X, and XIare fragmentary views in axial s ction that illustrate variations indetail hing pin of the structure typically shown II and VIII,

Referring first to Fig. I, a fuse body 5 of conventional outline carrieswithin itself a firing pin interrupter 3, and a booster charge i. Theinterrupter is of cylindrical shape and is contained in a bore that isformed within and extends transversely of the fuse body. A diametricalperforation through the interrupter is 8 Claims. (Cl. 102-73) filledwith a train of detonation initiating material that includes a primer 5.In the flight of the projectile the interrupter (released on firing)turns under centrifugal force from a remote position to the positionshown, in which the train of detonation-initiating material is alignedbetween the firing pin 2 and the booster charge a. It will be understoodthat, with respect to the interrupter, the showing is exemplary merely.It is essential to the invention only that there be within the fuse aprimer (or its equivalent) which at the moment of impact is subject tothe action of the firing pin.

The firing pin 2 is designed for facile traverse in the bore thatcarries it. It conveniently takes the form of a slender spindle ofpolished steel freely movable within the bore. The outer end of thefiring pin is enlarged and may conveniently be formed as a separateblock 6, arranged in an anterior enlargement of the bore. The block 6may for the sake of lightness be formed of aluminum; it is of circularcross-section; its outer surface is of convex curvature, advantageouslyspherical; its inner face may be formed with a re-entrant conicalrecess, within which recess it makes abutment upon the outer end ofspindle 2.

The firing pin, consisting of the spindle 2 and the block t, iscontained within the bore, so that at the tip the rim of the boreextends free of the forwardly convex face of the block 6. Preferably thefiring pin is contained wholly within the bore, and suitable means areprovided, such as a thin metal disk I secured at its rim for closing themouth of the bore.

In course of flight of the projectile the interrupter block 3 within thebody of the fuse comes to position; and at the instant of impact theparts are in the positions shown in Fig. I. If impact be on a lineexactly perpendicular to the target surface the firing pin will sustaina rearward thrust such as to pierce the primer 5 and fire the shell. Ifthe impact be on oblique line, operation in the manner illustrated inFig. II is effected. The rim of the bore is crushed, as indicated at a;the collapsing inner wall presses powerfully upon the convex outer faceof block 5 and by such pressure drives the firing pin rearward-aftersuch manner as an orange seed may be projected by pressing it betweenthe finger tips and then changin slightly the angle between the engagingfinger surfaces. The effect is the firing of the shell.

The rearward drive of the firing pin will be accomplished in any case inwhich the impact deforms the rim of the bore; and this deformation willoccur even though the angle of impact be less than the minimum at whicha projecting firing pin will be driven rearward in the fuse asheretofore known.

s indicated in Fig. III, the firing pin need not be formed in two parts,but may be an integral body 6| having the characteristics of shape andfunctioning in the manner already described.

Figs. IV and VI show firing pins formed in two parts, and they show thatthe block forming the outer portion of the firin pin may take the formof a sphere 60, abutting upon the outer end of the spindle 2. Thesefigures also show that the rim of the bore at the tip of the fuse bodymay be weakened for more ready deformation by the cutting of kerfs orslots 8 in it.

Figs. IV and V show that the block (or ball) 60 (62) may be restrainedwithin the bore (and the rearward thrust upon the block or ballintensified) by a forward tapering and diminution in the diameter of thebore, so that the forward face of the ball is engaged by a normallyoblique and tapering conical surface. Such refinement is renderedpracticable by providing a separate body 9 secured in a recess in thetip of the fuse body, which'body 9 may readily be shaped as describedbefore being assembled with the body 10.

Fig. VI indicates that the bore that carries the entire firing pin maybe formed in a body 90 cut from rolled stock. Such an article,manifestly, may be set in the body of any fuse prepared to receive it.

Fig. V further shows that the block 62 that forms the anterior portionof the firing pin, engaged as it is by the forwardly converging walls ofthe bore, need not be of appreciably convex shape forwardly.

When the fuse of Fig. I makes impact obliquely upon the surface of thetarget, the stress-transmitting line of contact of the laterally crushedtip of the fuse body with the surface of the head of the firing pinshifts in a direction extending from the base of the spherical head ofthe pin toward the apex, with the effect that the stress which drivesthe pin rearward is increasingly effective upon the firing pin. In thestructure of Fig. V, when the tip of the fuse is crushed under impact,the stress-transmitting line of contact of the conical bore portion ofthe fuse with the head of the firing pin shifts downward or rearwardupon such conical surface. Here too the increasing effect is to drivethe firing pin rearward.

Fig. V serves additionally to indicate that the firing pin, having thecharacteristics and assembled in the manner described, need not becontained wholly within the bore of the fuse body. It may be providedwith an extension 63 that protrudes from the mouth of the bore. Onperpendicular impact manifestly the firing pin will be driven rearwardlyin response to immediate impact upon the surface of the target.

The firin pin shown in Figs. I-VI is formed of rigid materialthroughout, and is effective by virtue of rigidity and shape.Alternately, the firing pin may be formed with a plastic anterior end,and the plastic portion, properly confined and made subject tocompression on the crushing of the rim of the confining bore, may impartto the posterior rigid spindle portion of the firing pin itsprimer-firing traverse. The operation in this case is comparable to thesqueezing of toothpaste from a collapsible tube.

In Fig. VII the rigid spindle-shaped posterior portion 20 of the firingpin is provided with a head 2|. An otherwise open ended capsule 22 ofthin and flexible material, snugly fitting within the bore, is appliedto and snugly encircles the head 2|. The enclosed space within thecapsule is filled with a suitable fluid material 23, such. for example,as finely divided graphite, preferably worked to a paste with vaseline.On the impact of the shell and the crushing of the rim of the bore inthe fuse body, the fluid-filled capsule is compressed from the forwardend rearwardly, as indicated at a, Fig. VIII, and the stress of impacttransmitted through the fluid material 23 drives the spindle 20 rearwardto perform its primer-firing function.

In Fig. IX the spindle is not headed; the enlarged anterior portion ofthe bore, beneath the snug-fitting capsule, is entirely filled withthefluid material; and the forward end of the spindle, extending int theenlarged portion of the bore, is snugly embedded in the fluid material.In this case the capsule may take the form of a brass cap 25 with convexanterior face, the fluid material 26 may be graphite worked to a pastewith castor oil, and the spindle 24 may be of aluminum. The functioningis as before, after the manner indicated in Fig. VIII.

In Fig. X the spindle of the firing pin is provided with a head thatfits snugly within the enlarged anterior portion of the bore; thecapsule is modified and becomes a disk 2'! that closes the boreforwardly, and all the space between the head of the spindle and theclosing disk is filled with fluid material. In this case the spindle maybe of steel and its head 28 of aluminum. The fluid filling 29 may be ofhydraulic soap or graphite.

In Fig. XI a structure otherwise resembling that of Fig. X isdistinguished, in that the enlarged portion of the bore is tapered at band reduced in diameter toward the rim (of. the structure of Fig. IV).This feature manifestly intensifies the stress that upon impact isexerted upon the spindle. The fluid material may be soap or talcfor talc(and, for that matter, graphite too) in finely divided form possessesfor the purposes in contemplation the qualities of a fluid, and is formy purposes a fluid.

I have specified a variety of preparations to constitute the fluidmaterial through which the stress of impact is imparted to the spindleof the firing pin. Neither of these particular preparations is specificto the form in connection with which I have described it, but all may beused interchangeably. It is characteristic of the materials specified,and is essential to the operation described, that they beincompressible, and so capable of transmitting stress instantly andwithout appreciable diminution.

I claim as my invention:

1. A point fuse for an artillery shell including a fuse body formed withan axial bore and a firing pin arranged within and movable in said boreand adapted in its rearward travel to fire the fuse, the firing pinincluding a posterior spindle and an interior deformable capsule,incompressible fluid material confined in the said capsule, thedeformable capsule being subject to the stress of deformation of the rimof the bore on impact, and adapted to transmit the stress through thesaid incompressible material rearwardly to the spindle.

2. A point fuse for an artillery shell including a. fuse body formedwith a forwardly opening axial bore and a firing pin arranged within andmovable in said bore and adapted in its rearward travel to fire thefuse, said firing pin including a posterior spindle portion and ananterior portion in the form of a collapsible capsule filled with stresstransmitting incompressible fluid material engaging the forward end ofthe spindle portion, the said capsule so filled being subject todeformation in response to the crushing of the rim of the bore on impactand adapted in such deformation to impart the stress of the crushing ofthe rim of the bore to the posterior spindle portion of the firing pin.

3. A fuse comprising a body having a tapering nose, an axial bore and anenlarged axial counterbore openin through said tapering nose to form adeformable rim section, a firing pin slidably fitting said bore, andhaving a plunger portion within said counterbore, a body of fluentmaterial within said counterbore, and means confining said materialwithin said counterbore in contact with said plunger means, whereby saidmaterial is compressed on deformation of said rim to rearwardlytranslate said pin.

4. In a fuse for an artillery shell, a fuse body having a reduced nose,there being a chamber in said body opening through said nose to form aweakened rim section, a body of fiuent material in said chamber, meansconfining said material in said chamber so that the same is compressedon deformation of said rim section on impact, and firing pin meanshaving a portion within said chamber to be operated by compression ofsaid material as aforesaid.

5. In a point fuse, the combination of a fuse body having a tapered noseand provided with an axial bore having an enlarged counterbore openingforwardly through said tapered nose to provide a weakened deformable rimat the fuse nose, a firing pin slidably fitting said axial bore, aprimer in said body in alignment with said bore and axially spaced fromand mounted independently of said pin, and means independent of saidfiring pin and slidably fitting said counterbore and operative to movesaid firing pin rearwardly into detonating engagement with said primerby and in response to deformation of said rim on impact.

6. In an impact fuse, a body having a tapered nose and a bore extendingaxially of said body and having an enlarged concentric counterboreopening through said nose to form a weakened deformable rim in saidnose, a firing pin slidably fitting said bore and having one endnormally projecting into said counterbore, a primer in said body inalignment with said bore, and mounted independently of said pin, andactuating means unconnected with said firing pin and slidably fittingsaid counterbore and engaging said pin to slide the same into detonatingengagement with said primer by and upon deformation of said rim uponimpact.

7. An impact fuse including a body having a frusto-conical nose of lowapex angle, there being a bore extending axially of said body and havingan enlarged concentric counterbore opening through the end of said noseto form in said nose, a weakened deformable rim section, a pin slidablyfitting said bore, a primer in said body in alignment with said bore andmounted independently of and spaced from said pin, and operating meansfitting in and independently slidable in said counterbore to engage saidpin to axially slide the same into detonating engagement with saidprimer upon movement in response to impact deformation of said rimsection.

8. In a fuse of the type described, a fuse body having a tapered nose,and an axial bore, an enlarged axial counterbore opening through saidnose to form a weakened rim section deformable on impact, a firing pinslidably fitting said bore and extending forwardly into saidcounterbore, a primer in said body in alignment with said bore andmounted independently of said pin, and a ball fitting said counterboreand positioned to be positively forced rearwardly by deformation of saidrim section on impact, to thereby axially translate said pin intodetonating engagement with said primer.

JOHN B. SEMPLE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,356,633 Kirchlofi Oct. 26, 1920340,935 Butler Apr..27, 1886 1,321,455 Kennedy Nov. 11, 1919 1,462,173Haas July 17, 1923 399,879 Graydon Mar. 19, 1889 1,316,607 Watson Sep.23, 1919 1,666,792 Remondy Apr. 17, 1928 444,537 Merriam Jan. 13, 18911,313,651 Sutton Aug. 19, 1919 1,318,098 Midgley Oct. '7, 1919 1,758,635Weiser May 13, 1930

